Clear defaults is blank (no defaults set). I can only clean the cache or the data. I deleted both and it still launches the HTCs' default app when I click over a video
I´ve even installed a couple of new video apps to see if the system would ask me which one I want to use...but no luck. The only way I can choose to use another app to play my videos is by long pressing the video file and then selecting "open with'...but I don´t want to do that.